IDO2 and systemic lupus erythematosus: Building on our prior work showing upregulated indoleamine 2,3‐dioxygenase (IDO) expression and reduced co‐stimulatory markers in probiotic‐treated DCs (Esmaeili et al. 2018; Babazadeh et al. 2025; Ahmadi et al. 2025), we found that these DCs significantly increase Treg frequencies (Figure 1A) through elevated FOXP3 and TGF‐β expression while reducing Th17 and Th1 populations in SLE patients (Figures 2 and 3).